CODEWITHSUNDEEP
pythonvtkmeshlab
AnandJ
AnandJ

Reputation: 386

mesh decimation in python

I have a high resolution triangular mesh with about 2 million triangles. I want to reduce the number of triangles and vertices to about ~10000 each, while preserving its general shape as much as possible.

I know this can be done in Matlab using reducepatch. Another alternative is qslim package. Also there is decimation functionality in VTK which has python interface, so technically it is possible in python as well. Meshlab is probably available in python as well (?).

How can I do this kind of mesh decimation in python? Examples would be greatly appreciated.

Upvotes: 6

Views: 11562

Answers (5)

Sara
Sara

Reputation: 45

Arguably a better option is to use pyfqmr (Python Fast Quadric Mesh Reduction). It is also integrated with other projects, including SurfIce and ThreeJS to name a few. It works in a matter of milliseconds!

Upvotes: 0

Fedor
Fedor

Reputation: 21221

Another option is to apply open-source library MeshLib, which can be called both from C++ and Python code (where it is installed by pip).

And the decimating code will look like

import meshlib.mrmeshpy as mr

# load high-resolution mesh:
mesh = mr.loadMesh(mr.Path("busto.stl"))

# decimate it with max possible deviation 0.5:
settings = mr.DecimateSettings()
settings.maxError = 0.5
result = mr.decimateMesh(mesh, settings)
print(result.facesDeleted)
# 708298
print(result.vertsDeleted)
# 354149

# save low-resolution mesh:
mr.saveMesh(mesh, mr.Path("simplified-busto.stl"))

Visually both meshes look as follows: enter image description here

Upvotes: 2

HB87
HB87

Reputation: 413

Best elegant and most beautiful Python decimation tool using meshlab (mainly MeshlabXML Library) can be found in this Dr. Hussein Bakri's repository https://github.com/HusseinBakri/3DMeshBulkSimplification

I use it all the time. Have a look at the code

Upvotes: 0

Daniil Nikulin
Daniil Nikulin

Reputation: 51

I would recommend you to use vtkQuadricDecimation, the quality of the output model is visually better than using vtkDecimatePro (without proper settings).

decimate = vtkQuadricDecimation()
decimate.SetInputData(inputPoly)
decimate.SetTargetReduction(0.9)

One of the most important things is to use Binary representation when saving STL:

stlWriter = vtkSTLWriter()
stlWriter.SetFileName(filename)
stlWriter.SetFileTypeToBinary()
stlWriter.SetInputConnection(decimate.GetOutputPort())
stlWriter.Write()

Upvotes: 5

GioR
GioR

Reputation: 636

Here is a minimal python prototype translated from its c++ equivalent vtk example (http://www.vtk.org/Wiki/VTK/Examples/Cxx/Meshes/Decimation), as MrPedru22 well suggested.

from vtk import (vtkSphereSource, vtkPolyData, vtkDecimatePro)


def decimation():
    sphereS = vtkSphereSource()
    sphereS.Update()

    inputPoly = vtkPolyData()
    inputPoly.ShallowCopy(sphereS.GetOutput())

    print("Before decimation\n"
          "-----------------\n"
          "There are " + str(inputPoly.GetNumberOfPoints()) + "points.\n"
          "There are " + str(inputPoly.GetNumberOfPolys()) + "polygons.\n")

    decimate = vtkDecimatePro()
    decimate.SetInputData(inputPoly)
    decimate.SetTargetReduction(.10)
    decimate.Update()

    decimatedPoly = vtkPolyData()
    decimatedPoly.ShallowCopy(decimate.GetOutput())

    print("After decimation \n"
          "-----------------\n"
          "There are " + str(decimatedPoly.GetNumberOfPoints()) + "points.\n"
          "There are " + str(decimatedPoly.GetNumberOfPolys()) + "polygons.\n")


if __name__ == "__main__":
    decimation()

Upvotes: 6

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